Good that you spread her meds out.  That may be better than the twice daily dosing for the time being.  In fact twice daily dosing would probably not help at all given that if she is not her usual self, she may be metabolising cortisol a little faster than she usually would.  So what did you do, split the total daily dose into three equal parts?  It is just that possibly this may be lowering the morning and evening dose, and that may cause problems.  On double dosing you guys would be giving 10mg oper dose three times per day.  If her normal dose is 10mg in the morning and at night, then you have lowered it considerably by 4mg each dose. 

My concern was that that morning and evening dose ARE high as it is, but in illness may be just what was keeping her temp down at certain intervals.  Now you have lowered it by spreadng the doses out, it could be a problem.  it all depends on the seriousness of the illness though.